ok, so we have two lights. one in the dash and one in the overhead panel. Over head as indicated tells you when your level is low like 2 litres usually. the oil light in dash tells you pressure is low which is usually to late. Hence why they call it an idiot light. Because there is no indication of gradual oil pressure loss. It just comes on...so, like said; turn off car and call tow truck and cross fingers your motor isn`t toast.